Bone health is regulated in a tightly coupled metabolic process between bone formation (by osteoblasts) and bone resorption (by osteoclasts). In healthy bone these processes are in balance; however, these rates may become uncoupled due to diseases affecting this regulation (Paget's disease, metastatic bone cancer), or hormonal changes, as in postmenopausal women. When bone resorption occurs more than bone formation, a net loss in bone mineral density (BMD) results, which can lead to diseases such as osteoporosis. The traditional approach to measuring BMD is dual energy X-ray absorption (DEXA), reported as a T-score (standard deviation from mean BMD) or Z-score (standard deviation from age-matched BMD). However, DEXA is an expensive procedure, and is not readily available for general population screening. The development of a viable screening diagnostic exam for early detection of BMD loss is a long standing problem.